Hi Socopunk,
there you have it, the headlight retaining screws are M5-0.8 x 5mm long.
To be nitpickingly precise:- M5-0.8 chrome plated cross-point rose head screws x 5mm long with a 90º pointed tail.
But WTF, no matter what type of head it's got any M5-0.8 will work if it's 5mm or more in length and you don't really need the pointy tail if the holes are properly lined up.
And lastly, after (but only after) the replacement screws have been purchased and are in place you will remember where you put the original screws.